How to Check the Suction Pressure of a Dust Collector
- 1
A well-used U-tube manometer needing a rescue.pressure image by Dusan Radivojevic from Fotolia.com
Connect the ends of U-tube manometer to the dust collector. You may need to drill 7/16-inch-diameter holes--one in the entrance plenum just before the filter, and one just after the filter. Smooth the holes with emery cloth after drilling. Some units already come with plugged holes for aftermarket instrumentation. - 2). Push the ends of the tubing about 2 inches into the two holes. The slightly smaller holes should provide a smooth, snug fit.
- 3
Sometimes precision pressure switches can sense too much suction loss to signal an alert.pressostat image by photlook from Fotolia.com
Clean the dust collector's pre-filter and main-filter, or purchase and install new ones. Start the dust collector. The level in one side of the U-tube manometer will go up and the other side down. The suction side will be higher. - 4
A vacuum cleaner without enough suction is similar to a clogged dust collector.cleaning image by Pavel Vlasov from Fotolia.com
Add the two readings in inches to obtain differential pressure across the filter. For example, if the upper leg reads 2 inches and the lower leg 2 inches, the total differential across the filter is 4 inches. Compare the readings with the specifications in the dust filter's user manual for your specific unit. Most units are designed for normal running with 1 inch to 6 inches of differential across the filter. With any higher differential (lower suction pressure), flow through the unit will be too low, and the filter should be visibly checked for cleaning or replacement. - 5). Disconnect the tube in front of the filter. The manometer will go higher up than before.
- 6). Add the measurement of the two legs of the manometer again. This is the basic suction pressure of the dust collector's suction motor, behind the filtering, which you can also compare to the manufacturer's specification to see if any attention to this motor itself is necessary.
- 7). Reconnect the tube in front of the filter and disconnect the tube behind the filter. This is the suction pressure available to pull air into the front of the unit. This might be a very low pressure, in the range of 1 inch of water column. The manufacturer will also have a specification for this parameter. A leak in the collector housing could also cause this suction pressure to be too low.
